There are many types of vehicles which, during the routine course of their operation, are exposed to hazardous traffic conditions. Police cruisers and highway patrol vehicles often must re-enter moving traffic from a roadway shoulder after detaining another vehicle, or when intercepting a vehicle for speeding or another violation. Law enforcement vehicles operating on divided highways and boulevards often make U-turns to intercept a vehicle traveling in the opposing lanes, or to respond to a dispatch call.
However, law enforcement vehicles are by no means the only type of vehicle which routinely must operate in hazardous traffic conditions. For example, another emergency vehicle such as an ambulance or fire truck may also have to return to the roadway from a stopped position on the shoulder (e.g. after completing a call to an injury, wreck, or fire), or may have to make a U-turn to respond to a fire call or medical emergency.
Non-emergency vehicles also may have to make similar maneuvers, such as a construction or street maintenance vehicle, or a utility vehicle (e.g. telephone, electrical, water, sewage or natural gas service truck or van, or school bus). When completing a job or when attempting to arrive at a place for a job near or on a roadway, these types of non-emergency vehicles may be exposed to the same traffic hazards as a police vehicle, ambulance, or fire truck.
Therefore, the following description of certain hazardous situations applies equally well to all of these types of vehicles, and not just to police and highway patrol vehicles. For the remainder of this disclosure, we utilize the term “primary vehicle” to refer to any vehicle which is subjected to a potentially hazardous traffic condition, such as a police or trooper vehicle, or alternatively another emergency or non-emergency vehicle as previously described. Additionally, we employ the term “secondary vehicle” as a vehicle which may be involved in a particular scenario, the position and condition of which the operator of the primary vehicle is aware, such as a vehicle a patrolman has detained alongside a road, or a vehicle which an ambulance or fire truck is servicing. Further, we will refer to other vehicles which pose a potential danger to the primary vehicle as a “closing vehicle”, such as a vehicle which is moving in a lane of traffic in which the primary vehicle is entering, and especially of which the operator of the primary vehicle may not be aware.
Police cruisers and highway patrol vehicles are generally supplied with several types of equipment, including an enhanced engine, suspension, and braking systems, as well as voice and data communication equipment. Such vehicles are also equipped with a variety of rotating beacons, strobe lights, and LED warning indicators, which, when used separately or in conjunction with a siren, can provide warning to other motorists of the patrol vehicle's status and position. Many law enforcement vehicles are also equipped with radar guns which can determine the speed of a target vehicle in traffic, mainly for the purposes of enforcing roadway speed limits. While these types of devices are useful in many applications of law enforcement, they provide inadequate safety to the officers operating the patrol vehicle in certain scenarios.
For example, in one common law enforcement scenario (10) as shown in FIG. 1, a trooper vehicle T is traveling in a first direction at an initial position (14) on a lane (12) of a divided highway, wherein the divided highway also has a median (13) and an opposing traffic lane (11).
Initially, the trooper may be measuring the speeds of vehicles in the opposing traffic lane (11), using a police radar unit, such as determining the speed of vehicle A in an initial position (15) in front of the trooper vehicle T in its initial position (14). At this point, the police radar unit has a line-of-sight (17) from the trooper vehicle T to the vehicle A.
When the trooper decides to intercept vehicle A, he must make a U-turn maneuver (18) through the median (13), falling into a pursuit position (14′) traveling in the opposing lane (11) behind vehicle A, which has now moved to position A (15′).
However, if another vehicle B is also traveling (16) in the opposing lane (11) at the time of the trooper's U-turn maneuver (18), there may be a danger of a collision with the trooper's vehicle. Vehicle B may not be initially visible when the trooper turns due to poor roadway lighting, inclement weather, or another visual impediment. As the trooper must slow his speed during the U-turn, and regain highway speed following the U-turn, vehicle B may be closing on the trooper vehicle at a considerably faster speed. If the trooper is operating the emergency lights (e.g. strobes, beacons, etc.) or the siren, the operator of vehicle B may be alerted to the danger of collision with the trooper, but the trooper is provided no warning of the potential collision.
In this particular scenario, the trooper vehicle T represents a primary vehicle, the intercepted vehicle A represents a secondary vehicle, and the vehicle B with which a collision danger exists is the closing vehicle. In alternate versions of this scenario, the primary vehicle may be a fire truck, ambulance, utility van, school bus or maintenance truck. Even though there may not be an intercepted vehicle in such a variation of this scenario, there certainly can be a closing vehicle which presents a collision danger when the primary vehicle is making a U-turn.
In another common law enforcement scenario (20) as illustrated by FIG. 2, a trooper vehicle T (24) is initially stopped (24) alongside (21) a roadway (22), sometimes with a detained vehicle A, which is also stopped (25). Alternatively, the trooper vehicle T may not be accompanied by a detained vehicle A, such as the case when a trooper is “speed trapping” or investigating a situation to the side of the road.
As the trooper's transaction with the detained vehicle is completed, or when the trooper decides to return to patrol, he executes a driving maneuver (23) to return to the roadway (22) by pulling into the closest lane of traffic, such as by driving into position (24′). However, there may be another vehicle B traveling (26) in this same lane, approaching the trooper's position (24′). As the trooper is in transition from being stopped to achieving highway speed, the speed difference between the other-vehicle B and the trooper's vehicle T may be great, thereby increasing the danger of a collision. As with the previously described scenario, the trooper's vehicle's emergency lights, if engaged, may provide some warning to the operator of the other vehicle B, but do not warn the trooper of the impending danger.
In this second scenario, the trooper vehicle T again represents a primary vehicle, the detained vehicle, if any, represents a secondary vehicle, and the vehicle with which a collision potential exists represents the closing vehicle. In other scenarios such as this, a fire truck, ambulance, utility van, or maintenance truck may represent the primary vehicle.
Therefore, there is a need in the art for a system and method which provides detection of such possibly dangerous traffic conditions, and which provides an alerting function to a vehicle operator.